Research Articles
Control
Mohammad Shahi; Mohammad Reza Sohrabi; Sadegh Etedali; Abbas-Ali Zamani
Abstract
This research proposes an innovative process to locate devices in elevation using structural results in uncontrolled and controlled (passive and active) states, considering Soil-Structure Interaction (SSI) effects, especially for soft soil. Also, a Proportional Integral Derivative (PID) controller with ...
Read More
This research proposes an innovative process to locate devices in elevation using structural results in uncontrolled and controlled (passive and active) states, considering Soil-Structure Interaction (SSI) effects, especially for soft soil. Also, a Proportional Integral Derivative (PID) controller with active single and multiple control devices is used for tall buildings under earthquakes. In addition, the simultaneous and non-simultaneous tuning of the design parameters are examined. The results of applying PID with a Multiple Active Tuned Mass Damper (MATMD) compared with the Single-Active Tuned Mass Damper (SATMD) show that the proposed process of locating the control devices reduces responses significantly. It also reduces the computational efforts of the optimization noticeably. The results of the non-simultaneous tuning of design parameters in all states also indicate an increase in the instability potential of the structure compared with simultaneous tuning. On the other hand, the reduction of the Root Mean Square (RMS) of the responses compared with the uncontrolled state confirms the effective performance of the system during earthquakes. Therefore, this research helps researchers gain a new design vision of how to locate control devices in tall buildings without optimization calculations and how to set parameters in the presence of SSI effects.
Research Articles
Industrial Electronics
Mehran Jami
Abstract
In electric vehicles (EVs), the small size of the dc link capacitor results in significant voltage deviations when there are changes in load or uncertain fluctuations from the power resources. This causes a decline in voltage quality. To address the issue of low inertia, this study suggests the use of ...
Read More
In electric vehicles (EVs), the small size of the dc link capacitor results in significant voltage deviations when there are changes in load or uncertain fluctuations from the power resources. This causes a decline in voltage quality. To address the issue of low inertia, this study suggests the use of a fast-responding energy storage system, such as a supercapacitor (SC), which can replicate inertial responses through a specified control algorithm. A virtual capacitor and a virtual conductance are presented in this paper, which are implemented in the inner loop control, specifically the current loop control of SC, to effectively emulate inertia and damping and improves the battery lifetime by reducing the rate of charge and discharge. To assess the stability of the EV, a comprehensive small-signal model is developed, and the acceptable range of inertia response parameters is determined through eigenvalues analysis of the system. Numerical simulations are conducted to demonstrate the performance of the proposed control structure.
Research Articles
Control
Anwer Jalal Ali; Sirwan Shazdeh; Hassan Bevrani; Rahmatollah Mirzaei; Qobad Shafiee
Abstract
The primary objective of this paper is to address the adverse effects of active power fluctuations on grid-connected converters. One of the challenges in integrating high levels of solar photovoltaic power into the utility grid is the lack of inertia from converter-based resources. This paper proposes ...
Read More
The primary objective of this paper is to address the adverse effects of active power fluctuations on grid-connected converters. One of the challenges in integrating high levels of solar photovoltaic power into the utility grid is the lack of inertia from converter-based resources. This paper proposes a solution to this challenge by synthesizing additional inertia and damping properties using power electronics converters. They emulate the inertia and damping properties of synchronous generators. The paper discusses different approaches to achieving effective damping control in grid-connected converters. It proposes a genetic algorithm optimization tool to optimize virtual damping and inertia parameters. The goal is to suppress oscillations and ensure stable grid operation. The proposed method is evaluated in both time-domain and frequency-domain analyses. The simulation results demonstrate the validity of the optimization technique and implementation procedure. Using virtual inertia and damping properties ensures stable grid operation and improves the integration of solar photovoltaic power into the utility grid. The paper provides a detailed discussion of the approach, optimization tool, and simulation results, highlighting the effectiveness of the proposed method.
Research Articles
Control
Hamed Azadrou
Abstract
This paper explores the application of high-speed bearingless induction motors within compressor systems. These motors utilize two distinct electromagnetic fields to generate both torque and suspension forces, making them suitable for applications requiring high speed with an efficient operation. However, ...
Read More
This paper explores the application of high-speed bearingless induction motors within compressor systems. These motors utilize two distinct electromagnetic fields to generate both torque and suspension forces, making them suitable for applications requiring high speed with an efficient operation. However, a significant challenge arises from the interference between these fields, which can negatively impact motor performance. To address this issue, we propose a new rotor structure that mitigates the interference problem. The proposed structure is based on the utilization of multiple dual-pole rotors positioned together, each of which is electrically separate from the others. Subsequently, we focus on optimizing the motor's dimensions to enhance both torque generation and suspension force capabilities. To achieve this optimization, a modern genetic algorithm is employed, allowing for comprehensive exploration of the design space. The results of the proposed optimized motor are compared with those of a motor optimized using a conventional algorithm. The findings affirm the effectiveness of our approach in improving motor performance.
Research Articles
Power systems
Amir Ghaedi; Reza Sedaghati; Mehrdad Mahmoudian; Shahriyar Bazyari
Abstract
Due to the problems associated with overhead lines, underground XLPE cables are increasingly being used in power systems. The main cause of deterioration in these cables is insulation failure, primarily arising from the partial discharge phenomenon. One of the main challenges in online PD detection is ...
Read More
Due to the problems associated with overhead lines, underground XLPE cables are increasingly being used in power systems. The main cause of deterioration in these cables is insulation failure, primarily arising from the partial discharge phenomenon. One of the main challenges in online PD detection is the presence of various noises in the environment that must be eliminated. In recent years, various types of noise with different distributions, such as impulse noises generated by power electronic devices, have been introduced into the power system. Therefore, denoising techniques should be employed to filter out the noises and interferences present in the detected PD signal. Due to the non-stationary nature of PDs, this paper suggests using the wavelet transform method, which covers both the time and frequency domains, to remove various noises from PDs. Consequently, to determine the suitable mother wavelet transform, threshold, and number of decompositions, the characteristics of PD signals occurring in the cables are investigated through experimental tests. Additionally, because different noises exist in substations, the background noise at the measurement site is recorded as a reference noise to be used in the application of the wavelet-based noise removal process. This method is examined on a sample cable, and the results are discussed. Moreover, using the suggested method, the detection of PD signals in several 20 kV substations in Iran is carried out through the use of high-frequency current transformers connected to shield wires, oscilloscopes with high-frequency bandwidth, and MATLAB software.
Research Articles
Control
Fereshte Tavakoli Dastjerd; Farhad Shahraki; Jafar Sadeghi; Mir Mohammad Khalilipour; Bahareh Bidar
Abstract
The design and development of data-driven soft sensors is important to predict the concentration of perilous pollutants in industry effluents to protect environmental health. The aim of this research is to design a tail gas quality warning system in the sulfur recovery unit (SRU) based on H2S and SO2 ...
Read More
The design and development of data-driven soft sensors is important to predict the concentration of perilous pollutants in industry effluents to protect environmental health. The aim of this research is to design a tail gas quality warning system in the sulfur recovery unit (SRU) based on H2S and SO2 concentration soft sensor utilizing multi-state-dependent modeling method. The SRU in the petrochemical plant of ERG PETROLI, located in Italy, is selected as the study region for implementation of the warning system. The generalized random walk- multi-state-dependent parameter method (GRW-MSDP) for soft sensor design is proposed. The GRW-MSDP estimation system is based on multi-state-dependent modeling method by utilizing the extension of the generalized random walk model. The method has been developed by utilizing the algorithms of extended Kalman filter (EKF) and fixed interval smoothing (FIS). The quality warning system of tail gas based on the estimated concentrations of SO2 and H2S sends instructions to adjust the ratio of air to feed flow in the reaction furnace of SRU by plant operators. The results indicate that the proposed estimation system can be efficient in dealing with process non-linearity, high-dimensional values, and random missing data. The comparative discussion of GRW-MSDP technique performance with different soft sensing methods shows that the designed soft sensor model is more reliable with fewer input variables, lower complexity and relatively higher prediction accuracy. Furthermore, the great efficiency of the designed quality warning system is obvious from the good accuracy and F1-score values of 99.4% and 0.8951, respectively.
Research Articles
Industrial Electronics
Mohammad Amin Bahramian; Mazdak Ebadi; Ali Asghar Ghadimi
Abstract
This paper investigates the starting current of an AC/DC/DC converter, consisting of a three-phase diode bridge rectifier and a synchronous buck converter. The use of microprocessors in such converters increases the total cost and also reduces reliability due to EMI phenomena. For this ...
Read More
This paper investigates the starting current of an AC/DC/DC converter, consisting of a three-phase diode bridge rectifier and a synchronous buck converter. The use of microprocessors in such converters increases the total cost and also reduces reliability due to EMI phenomena. For this reason, by removing the microprocessor, a start-up plan including a limiting starting resistor and then soft starting the switching module is proposed in this paper. By modeling the system under different operating modes, a solution is presented to minimize the circuit startup period, which includes minimizing the bypass time of the startup resistor and reducing the switching soft startup period as possible. The proposed method has been implemented on a 15-kW converter feeding from a three-phase 380 V power grid and provides up to 300 Vdc/50 Adc to supply an electroplating pool. The results show that the sequential startup procedure, including using a 50 ohm/1500 w resistor for 3 seconds, and then bypassing it, then starting soft switching after half a second and during 1.5 s, can move this circuit to a steady state in 5 seconds, keeping current in all parts below half rated current.
